"The American Academy of Pediatrics recommends that infants be exclusively breastfed for about the first 6 months with continued breastfeeding along with introducing appropriate complementary foods for 1 year or longer." https://www.cdc.gov/breastfeeding/faq/index.htm

Pumping is challenging, if not downright degrading. Ask a working mother. It also doesn't work as well as you might think, both the baby and the mother need breastfeeding 2-3 hours apart, or else the lactation may stop. Formula is suboptimal, according to AAP and common sense.

This is exactly how the singleminded focus on one metric (equal wages or bust) goes awry. Both mothers and infants suffer the pressure on mothers to compete on equal footing with males at all times. Is it really that hard to give mothers the space (and financial support) to chose the well being of their infants and of themselves, and accept that course of action will inevitably lead to a small decrease in lifetime wages?

Even the ancients were well aware of the dangers of attempting to equalize everyone to the exact same standard. See the story of the Procrustes bed, https://en.wikipedia.org/wiki/Procrustes